README: drop numbers from headers
README: drop numbers from headers

The header size changes should be sufficient, plus it makes adjusting
the readme easier

v2: - split this change out of the meson patch

Acked-by: Eric Engestrom <de0b63cf2dfb1fae8ed3c3b4244856a05677d4f0@intel.com>

waffle-gl/waffle,waffle-gl/waffle,waffle-gl/waffle,waffle-gl/waffle